slope vs declension

slope and declension both are nouns.

Word	Noun	Adjective	Verb	Adverb
slope	Yes	No	Yes	No
declension	Yes	No	No	No

As nouns, declension is a hyponym of slope; that is, declension is a word with a more specific, narrower meaning than slope:

slope (noun)	declension (noun)
the property possessed by a line or surface that departs from the horizontal	a class of nouns or pronouns or adjectives in Indo-European languages having the same (or very similar) inflectional forms
an elevated geological formation	a downward slope or bend
	process of changing to an inferior state
	the inflection of nouns and pronouns and adjectives in Indo-European languages

slope (verb)	declension (verb)
be at an angle